CODEWITHSUNDEEP
r
Beta
Beta

Reputation: 1746

Looping over list

I've a list in this form:

s = c("aa", "bb", "cc", "dd", "ee","xx")

I want to loop over this list till all the elements are consider. Then I want to check if each element is not equal to "blank". If it's not I want to create a variable which is each element of "s" and concatenation of a constant string, say "_file". Finally stack each of these elements.

The code I created is the following. But it's giving me blank.

s = c("aa", "bb", "cc", "dd", "ee","xx")

t<-if(length(s)>0){
  for(i in s){
    if(length(s)>0){
      i2=i*"_file"
    }
    else{
      i2=''
    }
    i2<-c()
  }
}

I tried this as well. But it's running for long.

s = c("aa", "bb", "cc", "dd", "ee","xx")
t<-while(s!=''){
  for(i in s){
    if(length(s)>0){
      i2=i*"_file"
    }
    else{
      i2=''
    }
    i2<-c()
  }
}

Can anyone please help me?

Thanks!

Upvotes: 0

Views: 73

Answers (4)

Colonel Beauvel
Colonel Beauvel

Reputation: 31171

Just the 'very concise one liner'

paste0(Filter(nchar, s), '_file')

Upvotes: 2

akrun
akrun

Reputation: 887118

Here is an option with sub

sub("^([a-z]+)$", "\\1_file", s)
#[1] "aa_file" "bb_file" "cc_file" "dd_file" "ee_file" ""        "xx_file"

data

s <- c("aa", "bb", "cc", "dd", "ee", "", "xx")

Upvotes: 2

Buggy
Buggy

Reputation: 2100

Here's what I would do. I am sure there are even faster solutions...

s <- c("aa", "bb", "cc", "dd", "ee","xx")
s[nchar(s)>0]<-paste0(s,"_file")

That should do the trick

Upvotes: 1

sgibb
sgibb

Reputation: 25736

This could be vectorized using nzchar:

s <- c("aa", "bb", "cc", "dd", "ee", "", "xx")
paste(s[nzchar(s)], "file", sep="_")
# [1] "aa_file" "bb_file" "cc_file" "dd_file" "ee_file" "xx_file"

Upvotes: 3

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